The present invention relates to exhaust mixers, and more particularly, but not exclusively, relates to an exhaust mixer for a gas turbine engine that reduces the visibility of hot parts.
It is often desirable to mix exhaust from a gas turbine engine with cooler air. Such mixing is often utilized to reduce the noise level generated by gas turbine enginesxe2x80x94 especially those used to propel aircraft. Several devices to facilitate mixing have been developed that are placed in the path of exhaust exiting the engine; however, in many applications, these devices leave room for improvement.
Furthermore, in certain applications, it is desirable to reduce visibility of hot parts of the engine through the mixing device. Alternatively or additionally, it may also be desirable to block view of the hot regions of the device itself.
Accordingly, there is a demand for further contributions in this area of technology.
One form of the present invention is a mixer with improved line-of-sight blockage.
In an alternative form, an improved mixer has a number of lobes each shaped to block at least a portion of the hot inner surface of the mixer or hot parts of the exhaust portion of an engine coupled to the mixer. Preferably, the lobes are curved in a pattern selected to provide a desired degree of blockage. More preferably, the lobes generally twist about a reference axis corresponding to the mixer, such as the mixer""s centerline axis. However, in other embodiments of the present invention, the lobes may be shaped or oriented differently.
In another form, a mixer includes a number of radial lobes that each terminate in a radial end wall or fin. The mixer may include lobes that twist about an axis corresponding to the direction of working fluid flow through the mixer. The walls may include a curved edge to direct working fluid towards a centerline axis of the mixer. However, in other embodiments, the walls may be shaped differently in accordance with the present invention.
In still another form, a mixer is provided that includes a number of radially oriented troughs and a number of structures that each extend from a corresponding one of the troughs toward the centerline of the mixer. These structures may be in the form of fins or vanes that at least partially block hot parts. The mixer may alternatively or additionally include a curved or twisting pattern of the troughs relative to a reference axis to enhance line-of-sight blockage. For embodiments of the present invention including the structures extending toward the center of the mixer, these structures may also be arranged in a curved or twisted pattern.
In a further form, a multilobed mixer includes a number of hollow radial vanes that extend from troughs between adjacent pairs of the mixer lobes toward the center of the mixer to provide cooling fluid. The cooling fluid may be utilized to cool a centerbody of an associated engine. The mixer may additionally or alternatively include a curved or twisting pattern of lobes relative to a reference axis to enhance line-of-sight blockage. For embodiments of the present invention that include the vanes, the vanes may also be oriented or shaped to follow a curved or twisted pattern.
In other forms of the present invention, a mixer according to the present invention may be coupled to an engine used to propel a vehicle. The vehicle maybe an aircraft with the engine being of the gas turbine variety. In other embodiments, the mixer of the present invention is employed with a different vehicle type, such a land vehicle or a vessel that travels on or through the water. Also, a mixer according to the present invention may be utilized with any engine type as would occur to those skilled in the art.
Further forms, embodiments, objects, features, advantages, benefits, and aspects of the present invention shall become apparent from the drawings and description provided herein.